2:18
What’s DEP?
• Electrophoresis– Charged particles moving in uniform field
D ie lec tric pa rtic le
3:18
What’s DEP?
• Dielectrophoresis– Dielectric particles moving in non-uniform field
Dielectric particle
Die lectric particle
Positive DEP Negative DEP
4:18
What’s DEP?
• Theory bit– (the only time an equation appears in this
presentation… promise!)
232F E)K(Rer m
**
**
2)(
mp
mpK
j
*
5:18
What’s DEP used for?
• Cell movement can be manipulated by frequency changes, so DEP is good for cell collection and sorting
Morgan et al. Biophysical Journal 77 (1999) 516-525
6:18
What’s DEP used for?
• Compare cell viability
G.H. Markx, C.L. Davey / Enzyme and Microbial Technology 25 (1999) 161–171
7:18
What’s DEP used for?
• Compare effects of chemicals on cells
F.H. Labeed et al. / Biochimica et Biophysica Acta 1760 (2006) 922–929
8:18
What’s DEP used for?
• Predict cell properties
232F E)K(Rer m
9:18
What’s DEP used for?
• Everything’s fine and dandy BUT DEP is not available commercially, nor used widely– Despite being described back in 1950s
• …but why?– Small assays only
• Restricted to research use
– Time consuming• One spectrum takes 40-60 minutes
10:18
What’s DEP used for?
• The answer(?): Multiple experiments at the same time!– Different
frequencies, or– Same frequencies
10kHz 2MHz
300um
11:18
http://www.youtube.com/watch?v=lLZbr3vP-Zs
12:18
DEP: The setup
• What’s needed:
Imaging/recording device
Microscope
Electrode
Cells
Signal generator
13:18
DEP: The (new) setup
• What’s (really) needed:
Imaging/recording device
Microscope
Electrode
Cells
Multiple output signal generator
14:18
Real-time DEP
15:18
Real-time DEP
103
104
105
106
107
108
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
Frequency (Hz)
Nor
mal
ised
ligh
t in
tens
ity
DEP plots for Jurkat cells treated with valinomycin 100402 (10 mS/m)
Control
Valinomycin
16:18
Real-time DEP
105
106
05
1015
20
25-1
0
1
2
3
4
5
Frequency (Hz)
DEP spectrum for Jurkat cells treated with valinomycin 091216
Time (min)
Mod
al s
hift
17:18
Real-time DEP
• That’s it! (for now, hopefully)
• Any questions: – [email protected]– facebook.com/nahrizuladib
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